Mining machines with radially adjustable boring head



June 28, 1955 J. 5. ROBBINS ET AL MINING MACHINES WITH RADIALLY ADJUSTABLE BORING HEAD 5 Sheets-Sheet 1 Filed May 24, 1954 S M M m m JAMES 5. RUBENS ARL. A- WI LME:

MINING MACHINES WITH RADIALLY ADJUSTABLE BORING HEAD 5 Sheets-Sheet 2 Filed May 24, 1954 JOE INVENTORS JAMES S. ROBEWXS CARL A. WILMS June 28, 1955 J. s. ROBBINS ET AL 2,711,888

MINING MACHINES WITH RADIALLY ADJUSTABLE BORING HEAD Filed May 24, 1954 5 Sheets-Sheet 5 7 I25 A 5 :6 \26 5 59 m TO;= g

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'IIIIIIIIIII/A A INVENTORS' JAMEE 5. ROBE CARL. A. W.

June 28, 1955 J. 5. ROBBINS ET AL 2,711,838

MINING MACHINES WITH RADIALLY ADJUSTABLE BORING HEAD Filed May 24, 1954 5 Sheets-Sheet 4 INVENTORS JAMES E. R0 5W8 CARL A. ILMS FIG. 6

5 Sheets-Sheet 5 J. S. ROBBINS ET AL IOI.

June 28, 1955 MINING MACHINES WITH RADIALLY ADJUSTABLE BORING HEAD Filed May 24. 1954 FIG. &

MINING MACHINES WITH RADIALLY ADJUSTABLE BORING HEAD James S. Robbins and Carl A. Wilms, Chicago, Ill., as-

signors to Goodman Manufacturing Company, Chicago, lit., a corporation of Illinois Application May 24, 1954, Serial N0. 431,994

Claims. (CI. 262-7) This invention relates to improvements in mining machines of the boring type, employing a boring head having a plurality of radially extending arms each with 2ft plurality of cutter supports projecting forwardly. thererom.

One of the objects of the invention is to provide a hinged adjustment for swinging the arms forwardly to reduce the working diameter of the boring head for facilitating the withdrawal of the head from the back, and the maneuvering or" the machine as a whole in the mine.

A further object is to provide a parallelogram type of construction for the arms and their cutter supports where by the cutter supports are maintained in substantially parallel relation with the axis of rotation of the head in all positions of hinged adjustment of the arms, so that the head may cut effectively at varying diameters.

The invention may best be understood by reference to the accompanying drawings, in which:

Figure 1 is a front view of a boring head with the arms in fully extended position, and with kerfs and intervening cores from a mine face superimposed on the figure to better illustrate the working environment.

Figure 2 is a longitudinal sectional View of Figure 1;

Figure 3 is a view similar to Figure l, but showing the boring arm assembly in fully contracted condition;

Figure 4 is a longitudinal sectional view of Figure 3;

Figure 5 is an enlarged detail taken along the line 5-5 of Figure 2;

Figure 6 is a fragmentary, exterior side view of the boring head hub of Figure 2;

Figure 7 is an enlarged detail section taken along line 7--7 of Figure 4;

Figure 8 is a detail section taken along the line 8-8 of Figure 2; and

Figure 9 is an enlarged detail plan view of one of the longitudinal cutter supports carrying a cluster of cutter bits.

Normally, at least two boring head assemblies will be used on a mining machine. Since both may be identical, it is necessary only to describe one.

The boring head assembly is generally designated 21. Each assembly is made up of three arms 22 mounted on a hub portion 23 carried on a suitable housing or gear case 24.

Referring to Figure 2, each of the arms 22 is con structed on a parallelogram principle, with a rear arm member A parallel with a pair of spaced arm members B, B. Each of the arms A is pivoted on a pin 26 carried by the hub 23 and, likewise, each pair of arm members B, B is pivotally mounted on a pin 27 carried by the hub.

At the outer end of each arm 22 is an elongated cutter support 28, pivoted at 29 and 31, respectively, to the arm members A and B, B and terminating at its forward end in a cluster of cutter bits 32 for cutting an outer kerf 33 in the mine face. Likewise an intermediate cutter support 34 is pivoted at 36 and 37 to arm members A and B, B for cutting a kerf 38 with a terminal cluster of bits 39. And, similarly, a cutter support 41 pivoted at 42 and 43 carries a cutter bit cluster 44 for cutting an inner kerf 46.

The cutter supports 34 and 41 may be provided with outwardly projecting wedge or cam surfaces 47 and 48, respectively, for breaking off annular cores 49 and 51 formed between kerfs 33 and 38.

A hollow drive shaft or spindle 52, with a driving gear 53 fixed thereon, is rotatably journaled in the gear case 24 by roller bearings 54 and 56 in the front and back walls thereof. The shaft 52 has a flange 57 disposed forwardly of the gear case 24, and keyed, as at 58, 58, to a corresponding flange 59 of the tubular hub 23 which herein is fitted over the front extension 52a of the spindle. A plurality of bolt studs 62 couple the two flanges together to hold the hub on the spindle.

At the forward end of the hub 23 and attached thereto by cap screws 63 is a burster cone 64 of the usual type having forward cutter bits 66 and a superposed screw formation 67.

Referring again to the arm members A and B, B, a gear sector 68 is formed on the inner end of each arm A (Figure 2). On the rear side of each arm member A is formed a stop 69 (Figure 4) engageable with a stop bar 71 which is shown enlarged in Figure 7.

As best shown in Figure 5, the hub 23 is provided with three pairs of upstanding ears 72, 72. Each pair is provided with a cross-bore 73 for receiving pivot pin 26 of the rear arm A, which pin is held in place as by an external key 74 bolted at 76, '76 to one of the ears and engageable with a slot 77 formed near one end of the pin. Each pair of cars 72 also has a cross bore 80 for pivot pin 27 of arm members B, B.

Each of the cars 72 has a flattened top surface 78 formed rearwardly of the corresponding bore 73 for supporting the stop bar 71, held in place as by means of cap screws 79, 79. This construction is best shown in Figures 2, 4 and 7. As seen in Figure 2, the purpose of the stop bar 71 is to engage the stop 69 and limit the maximum diameter that can be cut by the boring head. The maximum cutting diameter may be varied by using stop bars 71 of different heights.

The pivot pin 27 for each pair of arm members B, B is held in place by cap pieces 82, 82, held against the outer faces of said arm members by bolts 83. As best shown in Figures 6 and 8, that portion of each pin 27 which is between the upstanding ears 72, 72 is trimmed away along the line 84 in order to avoid interference with the corresponding arm A in the fully contracted position.

As best shown in Figure 8, each of the pins 27 is fixed against rotation relative to the hub by a set screw 86 threadedly engaged with one of the corresponding ears 72.

The arm members A and the arm members B, B are parallel; likewise, the cutter supports 28, 34 and 41 are parallel, thus defining parallelograms which maintain the cutter supports and their bit clusters in operative mining positions over a wide range of diameters between the maximum illustrated in Figure 2 and the minimum illustrated in Figure 5. Adjustment of the cutting diameter is obtained by rotation of worm 37 which is meshed with each of the three sectors 68. The worm is carried by a shaft 88 rotatably journaled within bearings 89 and 91 carried in a sleeve-like retainer 92 mounted within spindle extension 52a. The sleeve 92 is held in place by a plurality of cap screws 93.

An adjusting shaft 94, journaled in bearings 96, 97 in the spindle, is connected by coupling 98 to shaft 88. Thus, as will be seen, the diameter of the cutting head may be adjusted by aflixing a wrench to the square end 99 of the shaft 94 and turning it in one way or the other.

The front wall of the gear housing 24 has a bearing 1 retainer plate 101 attached by means of a plurality of cap screws 102. The retaining plate contains an oil seal 103 bearing against a finished ring 104 held, as by means of a press fit, on the drive shaft 52. A spacer 106 maintains thev gear 53 in spaced relation with the bearing 54 and a. lock nut 107, threadedly engaged with the shaft, holds the gear in place. At the rear end of the shaft, the gear housing is formed with a bore 109 having a retainer ring 111 for the bearing 56. A cap 112, held in place by screws 113, serves as a retainer for double ball bearings 114, 114 which in turn bear against the ring 111. The bearings 114 absorb thrust reaction from the drive shaft 52 and themselves are mounted on a reduced end portion 116 of the shaft, being held in place by washer 117 and lock nut 118.

To control end play, the adjusting shaft 94 is provided with a shoulder 119 which is retained between the end surface 121 of cap 112 and a plate 122, the latter being held in place as by means of cap screws 123. It will be understood that there will be sufiicient clearance between members 112 and 122 to permit the shoulder 119 to rotate freely with the boring arm assembly 21.

Referring now more particularly to Figures 2 and 4, it will be seen that the hub 23 is cut away along cylindrical surfaces 121 and 122 to provide clearance for the gear sector 68. This is done at three positions, between each pair of upstanding ears 72, 72. The shaft is machined away at the same locations for the same reason.

In order to protect the interior of the shaft from ingress of dirt and the like, the inner end of each of the arms A is provided with a pair of arcuate wiper plates .3

123 and 124, each being the same width as the space between the ears 72, 72 (see Figure 4). Said plates are substantially concentric with pivot pin 26, but are preferably made of spring steel and maintained under tension so as to press resiliently against the cylindrical surfaces 121 and 122. The wiper plates 123 and 124 are held in place by any suitable means as for instance by cap screws 126, 127, 128 and 129.

In operation, the boring head assembly 21 will be used to mine out an opening of a diameter corresponding to the height of stop bar 71 employed. The higher the bar, the smaller the diameter, and vice versa. In backing out of a bore which has already been mined with this assembly, the arms may be retracted to their minimum diameter position as shown in Figure 4 by rotating the adjusting shaft 94 in the proper direction. For simplicity, the adjusting shaft has been shown as manually operable; in practice, it would usually be preferred to provide it with motor operating means, remotely controlled, by any suitable powered mechanism.

We claim:

1. In a boring head assembly for mining machines, a rotary hub having a plurality of radially extending cutter arms mounted thereon, each of said arms consisting of a parallelogram type linkage including two arm members connected to said hub on pivots spaced axially of said hub, and a plurality of forwardly projecting cutter supports each having their rear ends connected to said arm members on longitudinally spaced pivots, to maintain said cutter supports in substantially parallel relation with the axis 'of rotation of said hub in various positions of angular adjustment of said arm members relative to said hub axis.

2. The structure of claim 1, wherein said hub has means thereon for simultaneously adjusting said radial arms to their various angular positions relative to the hub axis.

3. The structture of claim 2, wherein one of the arm members of each radial arm hasa worm gear segment on its inner end engaged with a worm rotatably mounted in said hub concentric with the latter.

4. The structure of claim 3, wherein each gear segment is mounted on a single, centrally disposed arm member, and the other arm member of the parallelogram type linkage consists of a pair of laterally spaced arm portions.

5. The structure of claim 3, wherein the hub forms a hollow enclosure for the worm and the wall of said hub also has elongated slots through which the gear segments on the arm members project in close fitting lateral engagement, and said segments also have a slidable closure means at opposite ends thereof cooperating with said hub at adjacent ends of said slots.

No references cited. 

